Don't take a nap during the day, get tired during the day, 2 hours before without a phone, don't use the bed for any activity other than sleeping (using the phone, watching TV, eating, etc.) your brain will stop associating the bed with sleeping and it will be more difficult for you, the same thing happens if you sleep in a chair or desk for example: your brain associates it with sleeping and when you get to bed it will be difficult for you, don't eat a lot before sleeping, go to bed at the same time to make the habit little by little, turn off all the lights, regulate the temperature as pleasant as possible, try to have zero noise... a chamomile infusion at 9 PM and/or breathing exercises to relax can help